CHLOROPHYCEAE 
197 
If it is desired to mount whole branches showing the antheridium 
and oogonium in position, use the Venetian turpentine method, 
staining in Magdala red alone, or in Magdala red and anilin blue. 
Good mounts showing shield, manubrium, capitula, and filaments 
may be obtained by crushing an antheridium under a cover-glass. 
For this it is better to stain in Magdala red alone, since any over¬ 
staining is easily corrected by exposing the preparation to direct 
sunlight. 
As slides accumulate, the thoughtful student will feel the need 
of some kind of classification. Of course, one might arrange alpha¬ 
betically and there would be no need for thought; but we assume 
that the student who has made enough slides to need a classification 
will want one which expresses some idea of relationship, even if 
the idea may be more or less faulty. The classification indicated 
in Figure 46 is essentially that of Oltmann, and does not differ 
much from that given in Engler and Prantl’s Die natiirlichen Pflan- 
zenfamilien. If the student would compile similar diagrams in all 
the groups, his slides would mean, not only proficiency in technic, 
but an increasing knowledge of the structure, development, and 
relationship of plants. 
